Discharge valve mechanism in compressor

ABSTRACT

A discharge valve mechanism in a compressor for compressing refrigerant gas includes a valve plate and a discharge valve plate. The valve plate forms a discharge port into which the compressed refrigerant gas is discharged. The discharge valve plate is located between the valve plate and a rear housing and includes a support portion, a connecting portion and a discharge valve. The support portion is sandwiched between the valve plate and the end surface of the rear housing. The connecting portion is bendably cantilevered from the support portion. The connecting portion extends to an opposite side of the discharge port so as to bypass the discharge port from the support portion. The connecting portion has a free end portion. The discharge valve extends from the free end portion to the discharge port toward the support portion for opening and closing the discharge port.

BACKGROUND OF THE INVENTION

The present invention relates to a discharge valve mechanism in a compressor that is used for an air-conditioner.

Japanese Unexamined Patent Publication 10-141230 discloses a discharge valve mechanism in a compressor. Referring to FIG. 8, a gasket 106, a valve plate 109, a suction valve plate 111, a discharge valve plate 113 and a gasket 115 are interposed between a cylinder block 102 having formed therein a compression chamber 101 and a rear housing 105 having formed therein a suction chamber 103 and a discharge chamber 104 in the compressor. The valve plate 109 has formed therein a suction port 107 and a discharge port 108, and the suction valve plate 111 has formed therein a suction valve 110 for opening and closing the suction port 107. Also, the discharge valve plate 113 has formed therein a discharge valve 112 for opening and closing the discharge port 108, and the gasket 115 has formed therein a retainer 114. A piston (not shown) reciprocates in a cylinder bore 116. Thereby, the suction valve 110 is opened to introduce refrigerant gas from the suction chamber 103 into the compression chamber 101 through the suction port 107. Then, the refrigerant gas is compressed in the compression chamber 101. Further, the discharge valve 112 is opened to discharge the compressed refrigerant gas from the compression chamber 101 into the discharge chamber 104 through the discharge port 108.

Referring to FIG. 9, a plurality of the discharge valves 112 is formed in the discharge valve plate 113. In the discharge valve plate 113, a sandwiched portion 117 that is located inside the discharge valves 112, that is, inside the dotted line in FIG. 9 is sandwiched between the end surface of the rear housing 105 on the side of the cylinder block 102 via the gasket 115 and the valve plate 109 as shown in FIG. 8. The discharge valves 112 are cantilevered from the sandwiched portion 117 as a support portion.

When the refrigerant gas is discharged from the compression chamber 101 into the discharge chamber 104, the discharge port 108 is opened by bending the cantilevered discharge valves 112. The opening limit of the discharge valves 112 is restricted by the retainer 114 for preventing the discharge valves 112 from bending over its elastic limit.

However, when the opening limit of the discharge valves is restricted by the retainer, this restriction causes discharge resistance. Thus, there is a fear that compression efficiency of the compressor is decreased and excessive compression in the compression chamber is increased. The increase in the excessive compression in the compression chamber causes vibration of the compressor to increase, which leads to the problem of abnormal noise. In addition, load on compressor parts is increased due to increase in compressing force of the compressor. Thereby, the life of the whole compressor deteriorates, and expensive parts such as high strength element and high hardwearing element need to be utilized to maintain the life of the compressor. To solve such problems, it is presumable that the opening limit of the discharge valve is enlarged. However, when the opening limit of the discharge valve is merely enlarged, the discharge valve is broken by bend, or the discharge valve enters its plastic region so that the discharge valve fails to close the discharge port in a suction process.

To prevent the breakage of the discharge valve by bend as well as to enlarge the opening limit of the discharge valve within the elastic limit of the discharge valve, it is necessary to enlarge effective length of the discharge valve from the support portion that cantilevers the discharge valve to the discharge port. When the effective length of the discharge valve is enlarged, the opening limit of the discharge valve is also enlarged. In addition, since the discharge valve smoothly moves to open and close the discharge port, the discharge resistance is reduced. However, when a conventional discharge valve mechanism is utilized in the compressor whose body size generally has design limitation, the distance from the support portion, which cantilevers the discharge valve, to the discharge port is short to obtain the sufficient effective length of the discharge valve.

SUMMARY OF THE INVENTION

The present invention provides a discharge valve mechanism in a compressor in which the effective length from a support portion to a discharge port, that is, a sum of the lengths of a connecting portion and a discharge valve is enlarged, thereby the opening limit of the discharge valve is enlarged and the discharge valve smoothly moves to open and close the discharge port, so that the discharge resistance of refrigerant gas is reduced, compression efficiency of the compressor is improved and excessive compression in a compression chamber is reduced.

According to the present invention, a discharge valve mechanism in a compressor that includes a rear housing having an end surface for compressing refrigerant gas includes a valve plate and a discharge valve. The valve plate forms a discharge port into which the compressed refrigerant gas is discharged. The discharge valve plate is located between the valve plate and the rear housing and includes a support portion, a connecting portion and a discharge valve. The support portion is sandwiched between the valve plate and the end surface of the rear housing. The connecting portion is bendably cantilevered from the support portion. The connecting portion extends to an opposite side of the discharge port so as to bypass the discharge port from the support portion. The connecting portion has a free end portion. The discharge valve extends from the free end portion to the discharge port toward the support portion for opening and closing the discharge port.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

FIG. 1 is a longitudinal cross-sectional view of a compressor according to a first preferred embodiment;

FIG. 2 is a front view of a discharge valve plate according to the first preferred embodiment;

FIG. 3 is a partially enlarged cross-sectional view of the compressor according to the first preferred embodiment;

FIG. 4 is a front view of a discharge valve plate according to a second preferred embodiment;

FIG. 5 is a partially enlarged front view of a discharge valve plate according to a first alternative embodiment;

FIG. 6 is a partially enlarged front view of a discharge valve plate according to a second alternative embodiment;

FIG. 7 is a partially enlarged front view of a discharge valve plate according to a third alternative embodiment;

FIG. 8 is a partially enlarged cross-sectional view of a compressor according to prior art; and

FIG. 9 is a front view of a discharge valve plate according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A first preferred embodiment according to the present invention will be described in detail with reference to FIGS. 1 through 3. It is noted that, in FIG. 1, the left and right sides on the drawing respectively correspond to the front and rear sides of a compressor.

Referring to FIG. 1, a piston type variable displacement compressor (hereinafter compressor) according to the first preferred embodiment includes a cylinder block 1, a front housing 3 and a rear housing 6. The front housing 3 is fixed to the front end of the cylinder block 1 via a gasket 2. The cylinder block 1 and the front housing 3 have defined a crank chamber 4 as a control chamber. The rear housing 6 is fixed to the rear end of the cylinder block 1 via a valve plate 5. The rear housing 6 and the valve plate 5 have defined a discharge chamber 7 and a suction chamber 8. A gasket 9 is interposed between the cylinder block 1 and the valve plate 5, and a discharge valve plate 11 having formed therein a discharge valve 10 and a retainer plate 13 having formed therein a retainer 12 are interposed between the valve plate 5 and the rear housing 6. The cylinder block 1, the front housing 3 and the rear housing 6 are bolted by bolts that are not shown.

A drive shaft 14 is rotatably supported via radial bearings 15 a, 15 b in shaft holes that are respectively formed in the centers of the cylinder block 1 and the front housing 3. A shaft seal device 16 is provided on the front end side of the drive shaft 14 in the shaft hole of the front housing 3. A lug plate 17 is fixed to the drive shaft 14 in the crank chamber 4 to rotate integrally, and a swash plate 18 as a cam plate is provided on the drive shaft 14 such that the drive shaft 14 is inserted through a through hole that is formed in the swash plate 18. A hinge mechanism 19 is interposed between the lug plate 17 and the swash plate 18. Hinge connection between the lug plate 17 and the swash plate 18 through the hinge mechanism 19 and the support of the swash plate 18 by the drive shaft 14 allow the swash plate 18 to rotate integrally with and to incline with respect to the drive shaft 14 in accordance with sliding movement of the swash plate 18 along the rotational axis of the drive shaft 14.

A plurality of cylinder bores 20 is formed in the cylinder block 1 and arranged in the circumferential direction of the cylinder block 1. A piston 21 is accommodated in each of the cylinder bores 20 to reciprocate therein. In each of the cylinder bores 20, the piston 21 and the valve plate 5 have defined a compression chamber 22 whose volume is varied in accordance with the reciprocating movement of the piston 21. Each of the pistons 21 is engaged with the swash plate 18 via a pair of shoes 23. Thereby, the rotational movement of the swash plate 18 via the lug plate 17 and the hinge mechanism 19 in accordance with the rotation of the drive shaft 14 is converted into the reciprocating movement of the pistons 21 via the shoes 23. The lug plate 17, the swash plate 18, the hinge mechanism 19 and the shoes 23 constitute a crank mechanism that converts the rotation of the drive shaft 14 into compressing action for compressing refrigerant gas in the compression chambers 22.

The cylinder block 1 has formed therein a rotary valve accommodation chamber 24 where a rotary valve 25 is connected to the drive shaft 14 via a coupling 26 to rotate synchronously. The rotary valve 25 has formed therein a suction passage 27 that regularly communicates with the suction chamber 8. The cylinder block 1 has formed therein a communication hole 29 that intermittently interconnects the compression chambers 22 and an outlet 28 of the suction passage 27.

When the drive shaft 14 of the compressor rotates by driving power from an engine, the swash plate 18 is rotated via the lug plate 17 and the hinge mechanism 19, and the piston 21 reciprocates in the associated cylinder bore 20 via a pair of the shoes 23. When the piston 21 is in the suction process, the outlet 28 of the rotary valve 25 communicates with the communication hole 29, and the refrigerant gas is introduced from the suction chamber 8 into the compression chamber 22 via the suction passage 27. Then, when the piston 21 is shifted to a compression process or a discharge process, the communication hole 29 is closed by the outer peripheral surface of the rotary valve 25. When the piston 21 is in the discharge process, the refrigerant gas in the compression chamber 22 is discharged into the discharge chamber 7 via a discharge port 30 formed in the valve pate 25 by pushing away the associated discharge valve 10.

A relevant part of the present invention will be described now. FIG. 2 shows a front view of the discharge valve plate 11 according to the first preferred embodiment, and FIG. 3 shows a partially enlarged cross sectional view of the compressor.

Referring to FIG. 2, the discharge valve plate 11 has formed in its middle portion a through hole 31 through which the rotary valve 25 is inserted. The discharge valve plate 11 has also formed an annular support portion 32 that is located around the through hole 31 and is sandwiched between the front end of the rear housing 6 and the valve plate 5. A pair of protrusions 34 is connected to the outer periphery of the support portion 32 and each has formed therein a positioning hole 33. Six neck portions 35 are also connected to the outer periphery of the support portion 32. When the compressor is assembled, the positioning holes 33 are respectively fitted onto protrusions that are formed in the valve plate 5, thereby accurately positioning the discharge valve 10 at a predetermined position to be assembled.

The neck portion 35 is constricted from the support portion 32, and a pair of arm portions 36 protrudes from the neck portion 35 at a distance from each other. A free end portion 37 connects the ends of the arm portions 36. The neck portion 35, a pair of the arm portions 36 and the free end portion 37 constitute a connecting portion 38. The connecting portion 38 surrounds the associated discharge port 30. That is, the arm portions 36 that protrude from the neck portion 35 at a distance from each other extend toward the outside of the associated discharge port 30 or in the radial and outward direction of the valve plate 5, so as to bypass the associated discharge port 30. Also, the discharge valve 10 protrudes from the middle portion of the free end portion 37 to the associated discharge port 30 toward the support portion 32, that is, in the radial and inward direction of the valve plate 5.

Referring to FIG. 3, the discharge valve 10 receives the pressure of the refrigerant gas that is discharged through the discharge port 30 upon the discharge process of the refrigerant gas. Then, while the discharge valve 10 elastically bends about the free end portion 37 as a supporting point, the connecting portion 38 elastically bends about the support portion 32 as a supporting point. The limit of the elastic bend of the discharge valve 10 is restricted by the retainer 12 such that the discharge valve 10 bends within its elastic limit. Similarly, the limit of the elastic bend of the connecting portion 38 is restricted by a root portion 39 of the retainer 12 such that the connecting portion 38 bends within its elastic limit:

According to the discharge valve mechanism of the first preferred embodiment, the following advantageous effects are obtained.

(1) It is presumable that a substantial effective length from the support portion 32 to the discharge port 30 corresponds to a sum of the lengths of the connecting portion 38 and the discharge valve 10. Since the opening limit of the discharge valve 10 corresponds to a sum of the limits of the elastic bend of the discharge valve 10 and the connecting portion 38, the opening limit of the discharge valve 10 is set large. Thus, the discharge resistance of the refrigerant gas is reduced, so that compression efficiency of the compressor is improved and the excessive compression in the compression chamber 22 is reduced. Due to the reduction in the excessive compression in the compression chamber 22, vibration and abnormal noise of the compressor are reduced, and compressing force is also reduced. Consequently, load on internal parts of the compressor is reduced due to the reduction in the compressing force, and the life of the compressor is extended.

(2) It is presumable that a substantial effective length from the support portion 32 to the discharge port 30 corresponds to the sum of the lengths of the connecting portion 38 and the discharge valve 10, and the effective length is extended in limited internal space of the compressor. Thus, the discharge valve 10 smoothly moves to open and close the associated discharge port 30. Therefore, since the discharge resistance of the refrigerant gas is reduced, it is achieved that the compression efficiency of the compressor is improved, the vibration and the abnormal noise of the compressor are reduced and the life of the compressor is extended similarly to the above advantageous effect (1).

(3) Upon the discharge process, stress concentration is distributed to the free end portion 37 as the supporting point for the discharge valve 10 and the support portion 32 as the supporting point for the connecting point 38. Thus, stress of the neck portion 35 is reduced. In addition, a part of the neck portion 35 near the support portion 32 on which the stress concentrates most has a relatively large width so as to maintain its strength. Therefore, the durability of the neck portion 35 is maintained even though the neck portion 35 is constricted except the above large width part of the neck portion 35 near the support portion 32. Meanwhile, the constricted part of the neck portion 35 is easy to bend, so that the discharge valve 10 more smoothly moves to open and close the associated discharge port 30.

A second preferred embodiment will be described with reference to FIG. 4. In the following description about the second preferred embodiment, only the difference from the first preferred embodiment is described. Also, the substantially identical or corresponding elements are referred to as the same reference numerals as in the first preferred embodiment, and the detailed description is omitted.

Referring to FIG. 4, a discharge valve plate 41 has formed in its outer periphery an annular support portion 42 that is sandwiched between the rear end of the cylinder block 1 and the end surface of the outer peripheral wall of the rear housing 6. A pair of protrusions 43 is connected to the inner periphery of the support portion 42 and each has formed therein a bolt through hole 43 a through which a through bolt is inserted. Six neck portions 44 are also connected to the inner periphery of the support portion 42. The neck portion 44 is constricted from the support portion 42, and a pair of arm portions 45 protrudes from the neck portion 44 at a distance from each other. A free end portion 46 connects the ends of the arm portions 45. The neck portion 44, a pair of the arm portions 45 and the free end portion 46 constitute a connecting portion 47. The connecting portion 47 surrounds the associated discharge port 30. That is, the arm portions 45 that protrude from the neck portion 44 at a distance from each other to extend toward the inside of the associated discharge port 30 or in the radial and inward direction of the valve plate 5, so as to bypass the associated discharge port 30. Also, a discharge valve 48 protrudes from the middle portion of the free end portion 46 to the associated discharge port 30 toward the support portion 42, that is, in the radial and outward direction of the valve plate 5.

In the second preferred embodiment, the effective length from the support portion 42 to the discharge port 30 is extended in the limited internal space of the compressor similarly to the above-described first preferred embodiment. Thus, the opening limit of the discharge valve 48 is set large, and the discharge valve 48 smoothly moves to open and close the associated discharge port 30. Therefore, the discharge resistance of the refrigerant gas is reduced, so that compression efficiency of the compressor is improved and the excessive compression in the compression chamber 22 is reduced. Due to the reduction in the excessive compression in the compression chamber 22, vibration and abnormal noise of the compressor are reduced, and the compressing force is also reduced. Consequently, the load on the internal parts of the compressor is reduced due to the reduction in the compressing force, and the life of the compressor is extended.

The following alternative embodiments may be practiced according to the present invention.

Referring to FIG. 5, a connecting portion 51 does not has a neck portion and has a pair of arm portions 53 protruding from a support portion 52 at a distance from each other and a free end portion 54 connecting the ends of the arm portions 53. In this case, the effective length from the support portion 52 to the discharge port 30 is similarly extended. Thus, the opening limit of the discharge valve 10 is set large, and the discharge valve 10 smoothly moves to open and close the associated discharge port 30. Therefore, the discharge resistance of the refrigerant gas is reduced, and the excessive compression in the compression chamber 22 is reduced.

Referring to FIG. 6, the ends of a pair of arm portions 61 that protrude from a neck portion 35 at a distance from each other are not connected to each other, and a discharge valve 64 is formed to protrude from free end portions 62 of the arm portions 61 toward the support portion 63. In this case, the effective length from the support portion 63 to the discharge port 30 is similarly extended. Thus, the opening limit of the discharge valve 64 is set large, and the discharge valve 64 smoothly moves to open and close the associated discharge port 30. Therefore, the discharge resistance of the refrigerant gas is reduced, and the excessive compression in the compression chamber 22 is reduced.

Referring to FIG. 7, a connecting portion 72 includes a neck portion 71 that is not constricted. In this case, the effective length from the support portion 32 to the discharge port 30 is similarly extended. Thus, the opening limit of the discharge valve 10 is set large, and the discharge valve 10 smoothly moves to open and close the associated discharge port 30. Therefore, the discharge resistance of the refrigerant gas is reduced, and the excessive compression in the compression chamber 22 is reduced.

The present invention is applied to the single-headed piston type variable displacement compressor that utilizes the rotary valve for a suction mechanism in the above-described preferred embodiments. However, if a compressor utilizes the discharge valve, the present invention is applied to a compressor that utilizes a suction valve for the suction mechanism, a double-headed piston type compressor, a fixed displacement compressor or a wobble type compressor.

Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims. 

1. A discharge valve mechanism in a compressor that includes a rear housing having an end surface for compressing refrigerant gas, comprising: a valve plate forming a discharge port into which the compressed refrigerant gas is discharged; and a discharge valve plate located between the valve plate and the rear housing, the discharge valve plate including: a support portion sandwiched between the valve plate and the end surface of the rear housing; a connecting portion bendably cantilevered from the support portion, the connecting portion extending to an opposite side of the discharge port so as to bypass the discharge port from the support portion, the connecting portion having a free end portion; and a discharge valve extending from the free end portion to the discharge port toward the support portion for opening and closing the discharge port.
 2. The discharge valve mechanism according to claim 1, wherein the connecting portion includes: a neck portion formed so as to be constricted from the support portion; and a pair of arm portions protruding from the neck portion at a distance from each other, each of the arm portions having an end, wherein the free end portion connects the ends of the arm portions.
 3. The discharge valve mechanism according to claim 2, wherein the support portion has an annular shape and an outer periphery, the neck portion being connected to the outer periphery of the support portion.
 4. The discharge valve mechanism according to claim 2, wherein the support portion has an annular shape and an inner periphery, the neck portion being connected to the inner periphery of the support portion.
 5. The discharge valve mechanism according to claim 1, wherein the connecting portion includes a pair of arm portions protruding from the support portion at a distance from each other, each of the arm portions having an end, wherein the free end portion connects the ends of the arm portions.
 6. The discharge valve mechanism according to claim 1, wherein the connecting portion includes: a neck portion formed so as to be constricted from the support portion; and a pair of arm portions protruding from the neck portion at a distance from each other, each of the arm portions having an end, wherein the free end portion is provided at each of the ends of the arm portions.
 7. The discharge valve mechanism according to claim 1, wherein the connecting portion includes: a neck portion connected to the support portion; and a pair of arm portions protruding from the neck portion at a distance from each other, each of the arm portions having an end, wherein the free end portion connects the ends of the arm portions.
 8. The discharge valve mechanism according to claim 1, wherein the compressor is used for an air-conditioner.
 9. The discharge valve mechanism according to claim 1, further comprising a retainer having a root portion for restricting bend of the discharge valve, wherein bend of the connecting portion is restricted by the root portion.
 10. The discharge valve mechanism according to claim 1, wherein the discharge valve bends about the free end portion, the connecting portion bending about the support portion. 